hard to believe

deacon · #1 (**permalink**) 10-08-2009, 01:55 PM

I went to the bike store to buy a larger chain ring for one of my rhino bikes. They introduced me to a guy who had a $2500 hub motor bike with lithium ion batteries. He told me he could ride the bike four hours before he needed to recharge. I didn't tell him that I didn't believe him, I just asked how many amp hours the batteries were rated. He didn't have a clue. He said that the batteries discharged in watts as if he could measure the watts in the battery lol.

I'm not even sure he knew the volts. He did say one thing that would make me believe the batteries were better. he said the drain was constant. If that is true, then the batteries could last longer since they would be usable at the lower voltage after the drain begins. My sla batteries performance goes down as the voltage drops which happens pretty quickly. Even though they only drop a couple of volts the performance is so bad I am looking for a place to recharge them.

Does anybody know where I could find a range test comparison between lithium and sla batteries. I would like to see where someone actually tested the batteries side by side.

**2door** · #2 (**permalink**) 10-08-2009, 02:06 PM

Deac,
You might have a go here> Car-Go Battery
I deal with these folks a lot and they've always been very helpful. They also have some very good links on their web page. Hope this helps.
Tom

deacon · #3 (**permalink**) 10-08-2009, 05:58 PM

I have done some more reading and the batteries are also listed in watt hours so the guy at the bike store was right about that. However I have no idea since I just read that a 250 watt motor requires a 12 ah lith battery and that a 30ah would do for a 650watt motor. It all sounds a little complicated to me.

I have a feeling in the next year or two we will all know more about these batteries.

marts1 · #4 (**permalink**) 10-08-2009, 06:55 PM

Might want to put a hold on that and learn about the all knew batteries supposed to be on the shelves shortly..ya, what else is knew

Kevlarr · #5 (**permalink**) 10-08-2009, 06:57 PM

Lead acid batteries have more of a linear discharge rate (btw don't think that just because you have a SLA battery it means that it's a deep cycle) whereas Nicad and Li-ions tend to give almost full power then run down quickly when they reach their limit.

I think the guy is confusing how many watts his motor and controller is for what his batteries are and doesn't have a clue as to the Ah and discharge rating of his batteries.

Been a while since I figured this but if I remember right the "C" rating on a Li-ion is the discharge rate so for example if you have a 2600 mAh 20C pack you can discharge them at 20 times the mAh rating but like I said it's been a few years since I was on top of Li-ion technology.

Also if you have multiple sets of batteries you can go a long time before you have to charge all of them, even up to 4 hours so wonder if he did because that long of a continuous draw on one set, unless it's a massively over sized pack, seems a little tough to believe . lol

skyl4rk · #6 (**permalink**) 10-08-2009, 07:01 PM

They have been around for quite a while and are well known.

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deacon · #7 (**permalink**) 10-08-2009, 09:25 PM

The battery box was about five inches wide five inches high and 24 inches long at the very most. I thought it was pretty impressively small. I think if he could go 4hours he was almost totally pedaling.

Maybe he really meant that it took four hours to charge. That would really be more like it. He could have thought I asked him how long between charges, maybe he thought that is what I meant. He also mentioned that it had regenerative braking but at 25oo I sure as **** hope it did, and that it made coffee as well.

starrunner · #8 (**permalink**) 10-08-2009, 10:19 PM

deacon, with his 4 hour range claim, he was probably attempting to justify to himself for spending $2500 for the bike.

starrunner · #9 (**permalink**) 10-08-2009, 10:24 PM

Quote:

Originally Posted by marts1

Might want to put a hold on that and learn about the all knew batteries supposed to be on the shelves shortly..ya, what else is knew

I've been hearing about all those "knew" batteries that are just around the corner for so many years now that I just don't even worry about it anymore and just stick to what works at an affordable price right now. I quit listening to the bull long ago. If all these affordable, super long range, super quick charging batteries come along soon, that's great, but it seems it's always "next year".

deacon · #10 (**permalink**) 10-08-2009, 11:09 PM

I'm curious to see how much weight I can pull on one of my trailers. I might be able to pull that four hour battery pack in sla. Just need a big enough motor.